Donkey Kong Sound Issues - PCB v Mister FPGA 

That is great to hear! Hope to play the results soonish. :)

Yes and that is the main issue. MAME and Switch seem to have got it right. The reason that nobody goes back to original FPGA cores is because they are always chasing new releases and the next shiny thing. Very few of the developers want to become bug fixes for old cores they didnt release.

@@GeoffSuttorThat makes sense. Hopefully someone does eventually.

っぱj５

Software emulation has been in development since the late 90s. Hardware emulation for what? 2 years?

Yeah it really needs a good dev to dig into the soudn issue on this core and many others that are MAME sourced.

@@GeoffSuttor In case of Donkey Kong the main issue is that the sound comes from an analog source, which is hard to replicate in fpga! But that does not mean you cannot do it, if you are really willing to do it to get it right! They followed just the good enough route here. Later arcade cabinets do not have the problem anymore since they rely on dedicated soundchips instead of some analog sound logic! Of course mame has an easy task to do that, they just run whatever digitized sound data there is captured from the original! Emulation and FPGA have different points where things get really complicated, emulation always has a hard time to get the timing right, FPGA shows its limits when it comes to implement weird analog logic. Hence we have not seen any Laserdisc arcade games ported yet!

Hi Jace, Mr TG :) Thanks for dropping in. Not sure how this affects sound? MiSTer FPGA has the dips exposed in the OSD but they are not physical dips (although the sim would set them this way) imgur.com/a/KRkHczu . It was set for upright which is dip 8 on the PCB. The PCB on the left here is my original, the FPGA on right is direct capture from De10-nano HDMI.

Actually had a look at the video you are right about it drawing on backwards, although that is not the reason for this sound comparision it is odd that the dips in FPGA are set to upright yet it draws on like P2 - See this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-P8ASpoNNKqQ.html , there was a conversation about the diferences over on the MiSTer FPGA forum about the colours, the age of the implementaiton (like man years ago) and which rom set it would have been using. I haven't the technical nouce to understand it but was hoping someone would pick up the fix. Look slike someone might be on it. misterfpga.org/viewtopic.php?p=64024#p64024

Also you must have watched in frame by frame mode to see that! Lol. Here is FPGA using the FLIP option in the menus, it;s spot on (but color & sound is way off) - imgur.com/a/w9qdKeL

@@GeoffSuttor Ah, wasnt thinking of the sound issue at all. :) Just was noticing that it wasnt an identical side-by-side comparison. Its a habit that I've had to unfortunately develop. Listening to the audio difference it sounds like the cause is related to a filter/process not being replicated on the sound - but that is just a guess.

Possibly. I was actually working with a dev to try and get things sounding right, and we were making great progress. But some members of the community called his half finished work a regression, and he quit working on it. The walk sound you hear is the result.

@@turbochop3300 yeah the community with their everything must run under fpga otherwise it is not valid mentality is a pain in the... but that is only a handful of people a small minority. Most people who do not participate that much in the forums are pretty happy actually. The same discussions are over the ScummVM port, most are happy that it exists but the usual "arseholes" shout out loud that such a thing should not be ported onto the mister, which made the developer almost to give up!

​@@werpu12Yeah. He was working on the Donkey Kong audio, and afterward he was going to tackle the Votrax SC-01. But then he was met with some pushback, and he fled. I haven't heard from him since. I honestly hope he is alright.

Thing is doing analog audio loops old arcades within an fpga is close to impossible so go figure how much sense this bone headed approach by the fpga taliban makes. They rather live with emulated fake sounds so that it is in fpga instead of having real sounds being played by an emulation trigger!

Hi Retro Force, not sure what you mean. The volume isn't the issue, it's the high pitch of the analog sounds and the melodies are way off tone.

@@GeoffSuttor 🤣 I had to watch it again. 👍

It requires a simulation of analog circuits for each individual sound. Not exactly sn 'easy adjustment'. Read replies to other comments and links to MiSTer forum conversations and you will get more understanding of the issue.

The one on the left is a DK PCB so unsure how it is the wrong sound. :)

@@GeoffSuttor I said left twice (typo) my bad. The first one I meant the right side. But still if my ears are deceiving me..the left PCB sounds like one run sound repeated on a loop. Maybe I'm wrong.

@@TboneTenEighties The left PCB video is from the PCB analogue circuitry and sounds like every arcade DK PCB I've ever played at Kong Off's etc, so I'm assuming it is the correct analouge sounds. The right (FPGA) is digital only and samples that are incorrect.

@@GeoffSuttor The one on the left is in fact from an actual PCB, and it indeed does have the variation in pitch that the OP was describing, but it is, in fact, inaccurate. Why? Because the original arcade version uses a capacitor to change the pitch of the walking sounds. It sounds like that capacitor you have is going bad, and is no longer in perfect spec. Replacing that capacitor will indeed make the walking sound of your Donkey Kong PCB more "accurate" by giving it a greater range of potential pitch variation.

@@Ohrami The left "PCB" video is a direct capture of the arcade PCB through the edge connector of an original 1981 TKG4 arcade board into a "Mr Video" capture card which converts the RGB and Audio output signals to NTSC (S-video & RCA audio) for capture. It is peciveably identical to what I hear directly out of the DK speakers. Now if you are saying you believe my PCB has a bad capacitor, I would say to you that every PCB I've ever played on (and there has been a lot at the "Australian Kong Off's" have also bad capacitors because they all sound the same. The point of this video is to show how innacurate the MiSTer FPGA implementation is compared to a singal coming from an original arcade PCB. My 'guess' is that what you hear as a bad capacitor is simply the NTSC conversion process. Even with that, it sounds fine to me and I've heard many many original PCBs. The issue here is the FPGA sound, which is a travesty.

Speakers are irrelevant, these are direct captures from the PCB and MiSTer.

@@GeoffSuttor direct captures are irrelevant. You will be assimilated.

@@patsfan4life "I am the beginning, the end, the one who is many. I am the digital output."